Governing mechanism for turbines.



PATBNTED MAR. 26, 1907,

w. L. .R. EMMET. GOVERNING MECHANISM FOR TURBINES APPLICATION FILED JULY25. 1906.

2 SHEETS-SHEET 1.

' Witnesses:

' 14 /7060? L. REmmeb No 848,093. PATENTED MAR. 26, 1907 W. L. R. EMMET.GOVERNING MECHANISM FOR TURBINES. APPLICATION FILED JULY 25, 1906.

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WILLIAM L. .R. EMMET, 0F SCHENECTADY, NEW YORK, ASSIGNOR TO GEN- ERALEJJE(ITR1O COMPANY, A CORPORATION OF NEW YORK.

'GOVERNING MECHANISM FOR TURBINES.

Specification of Letters Patent.

No. 848,093. I fatenteo March 26, 1907. Application filed July 25,1906.Serial No. 327,599.

To all whom it may conce n: between strokes of the governor-controlledBeit known that LWILLIAML. R. 'Eiuisr, a citizen of the United States,residing at Schenectady, in the county of Schenectady T and State of NewYork, have invented certain new and useful Improvements in GoverningMechanism for Turbines, of which the T following is a specification. Thepresent invention relates to governing mechanism for turbines, and hasfor its object to provide a mechanism of improved construction which issimple and rugged in I character, reliable, and capable of close regullation in operation. I In carrying out my invention one or more 5suitable valves are provided which control one, two, three, or moreports, passages, i nozzles, or other fluid-discharging devices. Thelatter may admit motive fluid to the 1 wheel-huckets of the first stage,to those of a 1 subsequent sta.ge,or to both the admission and stagefluid-discharging devices. The valve or valves is or are provided with asuitable stem or actuator, and under normal operating COTHlll'lOllS theactuator and valve or valves is or are constantly moving to and fro by aslight amount to overcome static friction, the movei'nent being ejmtrollcd, prin'iaril v, by suitable. speed or load responsive device orgovernor and, secondarily, by a dash-pot or equivalent device. I arrangethe valve and spe d-responsive device in such manner that the valve isfor a given load positively moved in a direction to open it apredetermined number of times per minute, and the degree of said openingis determined by the load on the turbine. The secoi'idary governorcontrols the amount that the valve or valves will close after each ofsaid opening movements. To carry out this feature of the invention, Ihave chosen as an illustration a dash-pot which works freely orcomparatively so in opening the valve and which causes the valve toslowly close wholly or in partafter each opening. A suitable Weight,spring, or equivalent means is employed to close the valve when theeffect of the opening device or governor is removed. By properlyadjusting the relation of the dash-pot, spring, and governor the valveor valves will open to a predc terniined point for a given loadcondition 1 a. definite number of times per unit of time and slowlyclose by'a greater or less amount l pressure generator.

actuator. To state the matter in other words, the valve or valves arepositively opened, and as soon as the gQX'QI'IlOf-COD- trolled actuatorreverses its movement it or they start to close and continue to do sountil the governor-controlled actuator reverses and starts itsvalve-opening movement. By reason of these arrangements the valve orvalves will be floating,'so to speak, between two positions, whichdefine the limits of the region of movement of the valve or valves foranv given load, and said. region will vary as the load changes.

In the accompanying drawings, which illustrate one of the embodiments ofmy invention, Figure 1 is a view in side elevation of my improvedgoverning mechanism ap plied to a'turbine, certain of the parts beingbroken away for the purpose of illustration; and Fig. :2 is an end viewof the same.

1 represents a turbine of suitable construction. It may withadvantage beof the Curtis type; but the invention is applicable to other types ofturbines as well. 111 the particular turbine which I have chosen forillustrative purposes 2 represents the main shaft, upon which is mounteda wheel having one or more rows of peripheral buckets 3. Between thero'ws of wheel-buckets are intermediate buckets 4, that receive thesteam or other motive fluid from one row of wheelbuckets and afterchanging the direction dis charge the same against the adjacent bucketson the exhaust side. Fluid is admitted to the first row of buckets by anozzle 5 or other fluid-discharging device. The nozzle is-attached to asteam-chest 6 and the latter is bolted to the casing of the machine. Asingle stage. has been shown; but it is to be understood that theinvention is applicable to turbines having one or a number of stages.Instead of controlling the admission of motive fluid the mech anism maycontrol the passage of fluid from one stage to anotheror both admissionand stage control.

Fluid is admitted to theturbine by the supply-conduit 7, which may beconnected to a boiler or to a low-pressure suppl v-such,

for example, as the exhaust of another turme, a reciprocating engine, areceiver, or low- In the steam-chest is a piston-valve having one, two,or more heads or valves, depending upon the number of ter being securedto a suitable support-such,

for example, as the beari'ng-standardof' the main shaft. Between thepiston and a su table abutment is a compression-spring 14, tending atall times to force the piston downward and close the valve. Also mountedon the valve-stem is a yoke 15, by means of which .the valve ispositively opened by an amount depending upon the load conditions.

The speed-responsive mechanism for actuating the valve will now bedescribed. Mounted on the main shaft is a worm 16, Fig. 2, meshing witha worm-wheel 16 mounted on the low-speed shaft 17. On one end. of theshaft is mounted a fly-wheel 18 or other rotating element, and mountedthereon is apiv oted weight 19 (shown in dotted lines, Fig. 1) andarranged to move on its pivot in the plane of the fly-wheel.

20 represents the pivot for the weight, and 21 an extension-spring foropposing its movement. Mounted on the lever connecting the weights is awrist-pin 22, the orbit of which enlarges and diminishes as the load,and consequently the speed, of the turbine changes. As shown, the orbitof the wrist-pin would have the maximum diameter. As the load decreasesand the speed increases the axis of the Wrist-pin moves nearer andnearer to the axis of the low-speed shaft until it finally coincidestherewith, at which time the connecting-rod 23 has no movement.

Under normal working conditions the said rod has a-reciprocatingmovement, and once for each cycle it moves. the valve or valves to theirupper limit for the load then on the turbine, Situated in the base ofthe pillow block or standard and extending parallel with the low-speedshaft is a rock-shaft 24, the extent of move-- ment of which varies withthe load. On the end of the shaft away from the connecting rod is alever 25, which under normal operating conditions makes a certain numberof vibrations per minute, the amplitude of said vibrations beingdirectly dependent u on the load on the turbine. The free end 0 thelever is arranged to strike the lower end of the yoke 15 each time itmoves upward. By re ason of the dash-pot the valve does not fully closeeach time the lever moves downward, but moves only a certain distance.The amount that it moves down can be regulated to suit the loadconditions by adjusting the effect of the spring and the dash-pot. Onthe upward stroke the lever raises the yoke and the valve from the lowerposition to a given up er position determined by the throw of t e lever.Y

respectively.

It is evident that when the orbit of the wrist-pin 22 is at amaxin'ium'it will give the maxunum vibration of the governor-eontrolledlever or actuator 25, and hence all the valves will open their ports foreach stroke. As the size of the orbit of the wrist-pin decreases thethrow of the lever 25 will decrease, and therefore the upward movementof the valve-stem. Under certain conditions only one piston-valve headwill be opening and closing its port or ports wholly or in part; undergreat loads two pistonvalve heads, and soon. The parts are preferably soarranged that their weight assists in closing the valves; but thearrangement can be changed, if desired, to meet the requirements.

Steam or other motive fluid enters through the conduit 7 and fills thespace between the piston-valve heads 9 and 10 and also the spaces aboveand below the heads 5 and 10, Opposite each head is one or more portsleading to one or more passages in the nozzle 5'. The piston heads andports are so related thatthe head 10 iirst exposes a port, then theupper head S, and finally the ead 9. This gives successive opening andclosing of the ports.

The governor and the parts actuated thereby are so related to the valvethat the free end of the lever 25 will strike the under side of the yoke15 near the end of its travel and when the wrist pin 22 is passingthelower dead-center. By reason of this arrangenient the movement of thelever at the time it raises the valve or valves will be relatively slowand the effect of the blow will be at a minimum. If desired, I mayinterpose a resilient medium between the end of the lever andcooperating projection on the end of the yoke.

In accordance with the provisions of the patent statutes I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to to be the best embodiment thereof; butI desire to have it understood that the apparatus shown is onlyillustrative and that the invention can be carried out by other means.

lVhat I claim as new, and desire to secure by Letters Patent of theUnited States, is i. In a governing mechanism for turbines, thecombination of ayalve whose region of movement varies for differentloads, a speedresponsive device for changing the region of movement ofthe valve, and a means that acts to retard the movements of the valve inthe opposite direction.

2. In a governing mechanism for turbines, the combination of aregulating-valve, a governor which imparts a certain number of strokesto the valve in a given unit of time,

and a means which retards the movement of the'valve in the oppositedirection.

3. In a governing mechanism for turbines,

, moves the valve in the opposite direction and said actuator acting inopposition to said acthe combination of a regulating-valve, a governorwhich positively imparts to the valve? in one direction a given numberof strokes per interval of time, and a device which also retards it.

4. In a governing mechanism forturbines, the combination of aregulating-valve, a governor, a valve-actuator reciprocated directly bythe governor in one direction at a speed and through a distancedetermined by' the speed of the turbine, a retracting device for tuator,and means for retarding the efi'ect of said retracting device.

5. in a governing mechanism for turbines, the combination of aregulating-valve, a governor responsive to speed changes, a lever ac--tuated by said governor at a speed and through an angular distancedepending upon the speed of the turbine, a valve-actuator operated bysaid lever to open said valve, a spring for closing said valve, and aretarding device controlling the rate of closing.

6. In a governing mechanism forturbines, the combination of aregulating-valve, a gov-' ernor comprising a weight pivotedeccentrically to its axis of revolution, a lever connected to saidweight, a valve-stem operated by said lever in one direction, a springto move said valve in the opposite direction, and a dash-pot to controlthe rateof movement by said spring.

7. In a governing mechanism for turbines,

I trolling two or more ports in succession dul ing its travel, of avalve-stem, a governor comprising a revolving weight-pivoted eccentrically to the axis of revolution, a wrist-pin on said weight, whoseorbit of revolution varies in diameter inversely with the speed of theturbine, a lever connectedto said pin and retarded device for movingsaid stem in the opposite direction.

In witness whereof I have hereunto set- Witnesses:

BENJAMIN B. HULL, HELEN ORFORD.

actuating said stem ln'one d1rect1on, and a.

